Executives also gave insight on what the signing meant for their teams. Those in the National League, such as Phillies general manager Ruben Amaro Jr., were happy to hear Pujols had signed with an American League team.

"If that's the case, I'm glad he's out of our league," Amaro said.

Reds GM Walt Jocketty, who held the same position in St. Louis for much of Pujols' career, said Pujols leaving the NL Central cracked open the door in the division.

"I think it's a positive. When they lose a guy of that stature, it's pretty amazing," Jocketty said.

Brewers GM Doug Melvin said he was "a little surprised" to see Pujols leave St. Louis, though he is fully aware that's a possibility with all the high-profile free agents -- likely including one of his own, Prince Fielder.

While Melvin heaped praise upon Pujols for all his abilities and accomplishments, he also admitted the move won't necessarily make the Cardinals less of a threat in the NL Central next year.

"It depends on what [the Cardinals] do to replace him. I think when a player like that leaves your club, it leaves a big hole," Melvin said. "But when Carl Crawford left Tampa, [Fla.], they made the playoffs. He was their best player, even [though] he's not Albert Pujols.

"Albert impacted the club on the offensive side, the defensive side and also on the leadership and the presence."

Red Sox president Larry Lucchino was looking ahead to when his club would face the Angels.

"Every team has got its own reasons for doing what it does," Lucchino said. "Ten-year commitments are major commitments and risks, but I'm sure the Angels have their reasons for doing what they've done. It just makes for an even keener rivalry between the Red Sox and the Angels."

With the arrival of Pujols -- and left-hander C.J. Wilson, who agreed to a five-year, $75 million deal, also on Thursday morning -- the AL West, with the two-time reigning league-champion Rangers, becomes even more interesting. On Thursday, executives from all three competing teams agreed it just got a whole lot tougher to win the division crown.

"I can't handicap what this means for the Angels, but certainly when you end up with all the best players in the game in your division, that's not what you want," A's assistant GM David Forst said.

"The division just got significantly better," Rangers assistant GM Thad Levine said. "A team we have tremendous respect for and has been our main competition just got better. The challenge in the American League West just got bigger. But we feel our team is up for the challenge."

"That's a very special talent that they acquired and just makes it more difficult for everybody in the division," Mariners GM Jack Zduriencik said.

The Royals, who travel to Anaheim to open the 2012 season on April 6, will be the first to face Pujols in his new uniform in a regular-season game. Kansas City manager Ned Yost agreed with the consensus that the addition of Pujols makes the Angels a dangerous team.

"A player of that caliber is going to make any lineup better," Yost said. "The Angels have always been a quality team, they've always been a tough team. With their pitching and now with their added offense in the middle of the lineup that they have, it's going to be a very, very formidable team in that division and in the American League."

Cash Kruth is a reporter for MLB.com. Follow him on Twitter at @cashkruth. This story was not subject to the approval of Major League Baseball or its clubs.